In 1987, Ronald Reagan declared that the US was about to enter an incredible new era of technology.

Levitating high-speed trains, super-efficient power generators and ultra-powerful supercomputers would become commonplace thanks to a new breed of materials known as high temperature superconductors (HTSC).

"The breakthroughs in superconductivity bring us to the threshold of a new age," said the president. "It's our task to herald in that new age with a rush."

But 20 years on, the new world does not seem to have arrived. So what happened?

Early promise

Superconductivity was first discovered in 1911 by researchers at the University of Leiden who used solid mercury in their experiments.

Superconductors have no electrical resistance, so unlike conventional conductors they allow an electric current to flow through without any loss.

American Superconductor has also developed an electric motor using coils of superconducting wire for use in the next generation of US Navy destroyers.

Electric motors are used by most commercial cruise liners, but are typically very bulky.

Using HTSC technology dramatically shrinks their size and also increases their efficiency.

The company is just about to start testing its latest 36.5-megawatt engine that is cooled by off-the-shelf liquid helium refrigerators and weighs 75 tonnes. By comparison, an engine based on copper wires would weigh 300 tonnes.

"That's great for cruise ships and the navy, because they can use that space for other things like passenger cabins or munitions," said Dr Yurek.

"New age"

Experimentally, things have also moved on.

New superconductors have been found. For example, a new mercury-based compound has a transition temperature of 134K (-139C)

"When we applied pressure we raised it up to 164K (-109C) - that's a record," said Professor Chu.

"Of course from an application point of view, it's hopeless."

I think we're on a launching pad here and we're now ready to take off

Greg Yurek

However, other experimental work raises the possibility of discovering room temperature superconductors that would require no exotic cooling equipment.

A new theory, outlined in a paper in the journal Nature Physics by Dr Newns and his IBM colleague Dr Chang Tsuei, seeks to explain the elusive mechanism of superconductivity in the class of ceramics discovered in 1986.

"We don't see any fundamental limits," said Dr Tsuei.

"If someone discovered a room-temperature superconductor tomorrow that fits with what is outlined by our theory, we wouldn't be surprised at all," added Dr Newns.

This kind of optimism, seen for the first time in the mid-1980s, now seems to be deserved.

There has been a crescendo of research, while at the same time the first commercial HTSC products are rolling out of factories.

According to Dr Yurek, this is a sign that the new age promised by Ronald Reagan is finally here.

"I think we're on a launching pad here and we're now ready to take off," he said.